 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.internal.util;

 import org.eclipse.jface.action.ContributionItem;
 import org.eclipse.jface.action.IContributionManager;
 import org.eclipse.jface.action.StatusLineLayoutData;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.CLabel;
 import org.eclipse.swt.graphics.FontMetrics;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Label;

 /**
  * @issue needs Javadoc
  */
 public class StatusLineContributionItem extends ContributionItem {

     public final static int DEFAULT_CHAR_WIDTH = 40;

     private int charWidth;

     private CLabel label;

     /**
      * The composite into which this contribution item has been placed. This
      * will be <code>null</code> if this instance has not yet been
      * initialized.
      */
     private Composite statusLine = null;

     private String text = Util.ZERO_LENGTH_STRING;

     private int widthHint = -1;

     private int heightHint = -1;

     public StatusLineContributionItem(String id) {
         this(id, DEFAULT_CHAR_WIDTH);
     }

     public StatusLineContributionItem(String id, int charWidth) {
         super(id);
         this.charWidth = charWidth;
         setVisible(false); // no text to start with
 }

     public void fill(Composite parent) {
         statusLine = parent;

         Label sep = new Label(parent, SWT.SEPARATOR);
         label = new CLabel(statusLine, SWT.SHADOW_NONE);

         if (widthHint < 0) {
             GC gc = new GC(statusLine);
             gc.setFont(statusLine.getFont());
             FontMetrics fm = gc.getFontMetrics();
             widthHint = fm.getAverageCharWidth() * charWidth;
             heightHint = fm.getHeight();
             gc.dispose();
         }

         StatusLineLayoutData data = new StatusLineLayoutData();
         data.widthHint = widthHint;
         label.setLayoutData(data);
         label.setText(text);

         data = new StatusLineLayoutData();
         data.heightHint = heightHint;
         sep.setLayoutData(data);

     }

     /**
      * An accessor for the current location of this status line contribution
      * item -- relative to the display.
      *
      * @return The current location of this status line; <code>null</code> if
      * not yet initialized.
      */
     public Point getDisplayLocation() {
         if ((label != null) && (statusLine != null)) {
             return statusLine.toDisplay(label.getLocation());
         }

         return null;
     }

     public String getText() {
         return text;
     }

     public void setText(String text) {
         if (text == null) {
             throw new NullPointerException ();
         }

         this.text = text;

         if (label != null && !label.isDisposed()) {
             label.setText(this.text);
         }

         if (this.text.length() == 0) {
             if (isVisible()) {
                 setVisible(false);
                 IContributionManager contributionManager = getParent();

                 if (contributionManager != null) {
                     contributionManager.update(true);
                 }
             }
         } else {
             if (!isVisible()) {
                 setVisible(true);
                 IContributionManager contributionManager = getParent();

                 if (contributionManager != null) {
                     contributionManager.update(true);
                 }
             }
         }
     }
 }

